Normally vented liquid-storage tank for ships, with closure device for automatically preventing leaking if the ship should sink

ABSTRACT

A shipboard storage tank for liquids, such as petroleum products or chemicals. To prevent pressure buildup, and to permit overflow during filling, a vent and overflow conduit is provided. In order to prevent this vent and overflow conduit from becoming a source of pollution if the ship should sink and also in order to prevent loss of the contents of the tank upon sinking, the invention provides an anti-pollution valve installed in the conduit, which automatically closes the conduit, should the ship sink. The antipollution valve is actuated to its closed position by the hydrostatic pressure as the ship sinks and it automatically equalizes the pressures between the sea and the liquid within the tank as the vessel sinks to deeper depths. Transient effects, such as surface waves, are prevented from actuating the valve. The anti-pollution valve also includes means that make it possible to dump the liquid out from the tanks of sunken ships and thereby salvage it.

United States Patent [191 Seymour et a1.

[ NORMALLY VENTED LIQUID-STORAGE TANK FOR SHIPS, WITH CLOSURE DEVICE FOR AUTOMATICALLY PREVENTING LEAKING IF THE SHIP SHOULD SINK [75] Inventors: David Jackson Seymour; Norman MacRitchie, both of San Francisco; Parker J. Matthews, Millbrae, allof Calif; Thomas A. Clark, Seattle, Wash.

[731 Assignees: Jon G. Bowman; William E. Boeingt Wells McCurdy, part interest to each [22] Filed: June 14, 1972 [21] App]. No.: 262,741

[52] US. Cl. 114/74 R, 114/212 [51] Int. Cl B63b 25/08 [58] Field of Search 114/74 R,2ll,2l2, 16 D;

[561 References Cited UNITED STATES PATENTS 726,947 5/1903 Lake ll4/l6 D 803,176 10/1905 114/16D 1,414,560 5/1922 Fat ll4/2l2 1,851,084 3/1932 Brown et al. 114/212 2,327,055 23/1943 51 Mar. 4, 1975 2,357,059 8/1944 Ray 116/125 2,587,934 3/1952 Volpin 116/125 Primary E.\'aminerTrygve M. Blix Assistant Examiner-Stuart M. Goldstein Attorney, Agent, or Firm-Owen. Wickersham & Erickson [57] ABSTRACT A shipboard storage tank for liquids, such as petroleum products or chemicals. To prevent pressure buildup, and to permit overflow during filling, a vent and overflow conduit is provided. In order to prevent this vent and overflow conduit from becoming a source of pollution if the ship should sink and also in order to prevent loss of the contents of the tank upon sinking, the invention provides an anti-pollution valve installed in the conduit, which automatically closes the conduit, should the ship sink. The anti-pollution valve is actuated to its closed position by the hydrostatic pressure as the ship sinks and it automatically equalizes the pressures between the sea and the liquid within the tank as the vessel sinks to deeper depths. Transient effects, such as surface waves, are prevented from actuating the valve. The anti-pollution valve also includes means that make it possible to dump the liquid out from the tanks of sunken ships and thereby salvage it.

20 Claims, 16 Drawing Figures PATENTED 3.868 921 sum 10F g NORMALLY VENTED LIQUID-STORAGE TANK FOR SHIPS, WITH CLOSURE DEVICE FOR AUTOMATICALLY PREVENTING LEAKING IF THE SHIP SHOULD SINK BACKGROUND OF THE INVENTION This invention relates to the prevention of pollution of navigable waters and adjoining loci by leakage of polluting fluids from tanks of sinking and sunken vessels.

Liquid cargo and bunker tanks aboard a ship as parts of the ships structure have long been provided with vents and overflow pipes, mainly to enable the escape of air from the tanks during the filling and vacating operations, to prevent harmful vacuum conditions during off-loading, and to avoid the buildup of high pressures in the tanks during loading. These overflow pipes also prevent subjecting the ships structure to excessive pressures during the filling operation in the event of overfilling. Usually, the overflow pipes terminate in a gooseneck about three of four feet above the deck, depending on the depth of the tank. Some vent pipes may terminate at higher levels to avoid the accumulation of noxious or explosive gases at the deck level.

These vents and overflow conduits provide free venting at all times, for heretofore no vlaves or other restrictions have been incorporated in them. The American Bureau of Shipping does, however, required means for closing the openings in an emergency. This closure means is generally located at the end of the gooseneck and may comprise a floating ball check or hinged flap, operable either by hand or by the force of a submerging wave washing over the deck. Wooden plugs have often been inserted during heavy weather. Other types of closures are also in use. In addition, vents from tanks of gasoline and other volatile liquids are provided with screen-type flame arresters. All the closure devices are meant solely to prevent the entrance of sea water during temporary conditions of heavy weather when green water washes over the decks.

The present invention is concerned especially with what happens when a ship sinks and carries down tanks containing liquid petroleum products, chemicals, or other liquids which may be a source of pollution. Should the ship sink, many of her tanks will remain intact structurally, and, in fact, all may be intact if the sinking is solely due to flooding of reserve buoyancy compartments, such as the engine spaces or other dry compartments of the ship. If the vessel should sink while her vents are open, as may very well more often than not be the case, then as she sinks, water enters the tanks and replaces any air volume above the liquid, while that air escapes through the vents. Air that cannot escape, being pocketed or trapped, will then be compressed. As the ship sinks to greater depths, water continues to enter the tanks, further compressing trapped air until the pressure inside the tank becomes equal to that of the surrounding sea. Water, being of higher density than the gasoline, oil, or other petroleum or chemical products, settles to the bottom of the tank, forcing the petroleum products up and making them flow out from the overflow pipe, as more water seeps in to replace the oil. Millions of gallons of petroleum product or other chemical may thus escape and pollute the water.

This leakage obviously can become a serious source of oil pollution in sunken or partially submerged ships,

-with oil flowing from bunkers as well as cargo. Moreover, such cargoes and bunkers are lost. At present there is no device available for closing off the vents or ships or other vessels in such an event.

The present invention provides an overflow antipollution valve which a. does not restrict the vent or overflow passage area or otherwise prevent the vent or overflow function under normal operating conditions;

b. automatically closes the vent or overflow pipe when the vessel is submerged;

c. remains open and does not respond in the face of transient conditions such as a wave that breaks over the decks under normal voyage conditions;

d. continues to admit water to enter the tank during the submerging process to equalize tank pressure with that of the surrounding sea, in order to avoid collapse of the ships structure due to over pressure;

e. once equilibrium is reached that is, the vessel is on the bottom with sea and tank pressures equalized is not opened by transient pressures from waves at the surface;

f. operates independently of the ships orientation;

g. provides means for attaching a hose to enable a salvage ship to pump liquids out from the tanks of a sunken vessel; and

h. can be installed on existing vessels with minimum alteration to the ships structure.

SUMMARY OF THE INVENTION The invention provides a shipboard storage tank for liquids, whether they are cargo or for fuel, in which there is a vent and overflow conduit having an outlet and an anti-pollution valve installed in the outlet. The anti-pollution valve includes a closure device that automatically closes the conduit against the passage of liquids from the tank to the outlet.

Latching means normally latches the closure device in its open position so as not to interfere with the normal venting and overflow function, but a pressureactuated latch release acts on the latch means upon the application of a predetermined hydrostatic pressure, such as is exerted by water when the ship sinks. A conduit leading to the atmosphere from the pressureactuated latch release has an orifice in it that prevents actuation by transient effects, such as waves, while enabling prompt actuation by the ambient water pressure that is exerted by the closing of sea water over the ship.

The closure device preferably comprises a pivoted disc or clapper member and a strong spring for forcing the closure member to its closed position, once the latching means has been released.

The invention also includes access means for salvaging the liquid from the tank.

Other objects and advantages of the invention will appear from the following description of a preferred embodiment thereof.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a view in perspective of a liquid cargo tank embodying the principles of the invention and adapted for use in a vessel, such as a ship or a barge.

FIG. 2 is a somewhat diagrammatic view in side elevation of a cargo vessel embodying the principles of the invention.

FIG. 3 is a diagrammatic view in section of a typical prior-art tanker or bulk liquid cargo vessel, the section being taken through three tanks, each of which is fitted with two vents and overflow valves, one of which is shown in the drawing. There is some air in the top of each tank while the ship is floating on the sea, since such tanks are normally filled to about 95 to 98 percent of capacity in order to enable thermal expansion.

FIG. 4 is a view similar to FIG. 3 showing what happens when a prior-art vessel sinks and how oil leaks out through the vent under the prior-art conditions.

FIG. 5 is a view similar to FIG. 4 except that the vessel has sunk so that it lies on one side. 7

FIG. 6 is a view similar to FIG. 4 except that the vessel has turned over when sinking, so that the vents are on the bottom.

FIG. 7 is a diagrammatic view of a tank embodying the principles of the invention showing the two vents, one at each end of the tank, with the tank trimmed to a typical position in a sunken vessel.

FIG. 8 is an enlarged view with respect to FIG. 7 of one vent embodying the principles of the present invention.

FIG. 9 is a further enlarged view in elevation and in section of a portion of the vent of FIG. 8 showing a closure valve embodying the principles of the invention with the valve in its open or latched position and with the closed position indicated in broken lines.

FIG. 10 is view similar to FIG. 9 with the closure valve in its unlatched and closed position.

FIG. 11 is a view in section taken along the line 11-11 in FIG. 10.

FIG. 12 is a diagrammatic view in which a salvage operation is being carried on from a sunken vessel embodying the principles of the invention.

FIG. 13 is an enlarged view in perspective of an .indicator that indicates from the exterior what position the valve is in.

FIG. 14 is an enlarged view in section taken along the line l4l4 in FIG. 9.

FIG. 15 is a view similar to FIG. 14 with the member in a different position.

FIG. 16 is a view taken along the line l6-16 in FIG. 9.

DESCRIPTION OF A PREFERRED EMBODIMENT The present invention, as noted above, relates to the problem of preventing pollution from a sunken tanker or other vessel carrying polluting liquid, whether as fuel or as cargo.

Thus, FIG. 3 is a cross section through a vessel 10 having three tanks 11, 12, and 13 eachholding oil or some other polluting liquid. Each one of these tanks ll, 12, 13 has its corresponding set of vents, there being at least two for each tanks, although only one of them is shown in FIG. 1. Thus, a vent conduit 14 vents the tank 11, vent conduit 15 vents the tank 12, and vent conduit 16 vents the tank 13. In this state, with the vessel 10 floating in its normal operation, oil 17 fills about 95 to 98 percent of each of the tanks 11, 12,and 13, in order to enable thermal expansion safely, thereby leaving a small air volume 18 at the top of each tank. The vents 14, 15, and 16 prevent the buildup of pressure, and during a filling of the tanks with oil, provides for overflow in case the tank is overfilled, and also provides for escape of air during filling. During normal navigation, the vents 14, 15, and 16 are open to accommodate change in the pressure due to thermal effects. During storms they may, under the prior art, have been closed by wooden plugs or similar means, which can still be used, if desired, but these afford no protection if the vessel 10 should sink.

For example, as shown in FIG. 4, if a vessel 10 like that shown in FIG. 3 and representing the prior art, sinks and does not have the present invention applied to it, then the vents, 14, 15 and 16 let in water 19 and the water 19 first forces out the air 18 and then forces out the oil I7,'until the water [9 completely displaces the oil 17. The escape of air does no harm, but the escape of oil 17 does a lot of harm because it floats to the top and becomes an oil slick. Except for the doubtful advantage of letting someone know where the vessel sank, oil slicks do no good and they damage the environment, killing birds, fish, and other marine life, and in some cases, where the shipwreck takes place near the coast, causing severe problems on beaches and in harbors.

If the ship 10 should sink on its side (see FIG. 5), water 19 is again able to enter through the vents 14, 15, and 16 and to displace the oil 17 and, if the ship 10 sinks upside down, as shown in FIG. 6, some water 19 enters, but in this instance the oil 17 will not escape because it is trapped unless there is some damage to the hull itself or to the tanks. The air that is trapped within is compressed and does no harm either.

In the present invention, as shown in FIG. 2, a ship 20 has a tank 21 with a normal pair of vents 22 and 23, shown in FIG. 1. These enable the normal functions of vention and overflow. However, each one of the vents 22 and 23 is provided with a closure or valve sector 25, which may be retrofitted on existing vessels or may be provided as part of the original equipment on new vessels. As shown in FIG. 8, the retrofit lies below the outlet 24 for the vent 22 and is directly in the conduit line between the main tank 21 and the outlet 24 of the vent and overflow conduit 22. The valve sector 25 may be provided with a pair of flanges 26 and 27 and the conduit 22 may be provided with flanges 28 and 29 to receive the flanges 26 and 27, so that the sector 25 is removable and installable in existing installations. However, there may be a one-piece vent conduit-valve combination, if that is desirable. The valve can be designed to fit any size vent and overflow line from as small as one-half inch in diameter to the largest diameters used on liquid bulk cargo vessels.

As shown in FIG. 9, this closure device 25 incoporates an interior conduit 30 between the two flanges 26 and 27 having a valve seat 31 as an annular projection near its upper end facing down. A closure valve 32 may comprise a flat plate of suitable closure material having a latched extension 33 thereon with a latch dog 34 and the valve 32 may be mounted on an offset pivot 35 by means of a pivot lug 36. A coil spring 37, somewhat like the spring in a clock, may be used to provide a constant force tending to close the valve member 32, and the valve member 32 is prevented from closing only by the fact that the latch dog 34 holds the closure member 32 latched to an open position by engaging a latch 38, which itself is on an arm 40 that is mounted on a pivot 41.

The latch arm 40 has at the opposite end from the latch 38 a clevis 42 secured by a pin 43 to a rod 44. The rod 44 extends up into a cylinder 45 and a piston 46 is secured to its upper end. The piston 46 is mounted very close to the top of the cylinder 45 opposite to a cylinder head 47 and is backed up by a spring 48 which provides a desired pressure lower than that which will be applied to the piston 46 after the ship has sunk a few feet, if it should sink, but higher than anything that could be provided by the atmosphere. Air is normally led into the cylinder 45 at the head end just above the piston 46 by a conduit 50 having an orifice 51 of reduced size which prevents the entry of any substantial amount of water during the mere passage of a wave, even though the wave may be of large size. The conduit 50 leads up through a vertical portion 52, turns a right angle, and through a reduced portion 53, which also helps to prevent passage of transient effects, goes into a small chamber 54 above the piston 46. On the atmospheric side of the orifice 51, a pipe 55 is connected to an external protective strainer 56 to prevent foreign matter form entering and plugging it, and it is provided with a structure which prevents tampering. However, if it should be desired for any reason, such as to test operation, to close the valve 25, this can be done by applying a suitable pressure of compressed air, as by a hose fitting to the conduit 50. The valve 25 can then be reopened manually.

It will be apparent from the above that during normal operation, the tank 21 is vented,just as it is in the present-day fully vented operation. However, if the ship should sink, water 19 coming through the pipe 55, the orifice 51, and the conduit 50 gets into the chamber 54, pressure builds up rapidly, and moves the piston 46 down against the pressure of the spring 48. Once the piston 46 has been moved far enough to unlatch the latch 38, the large clock-type spring 37 quickly urges the valve member 32 to its closed position against the seat 31 and holds it closed with a very strong force. Some air may escape during this time, but little or no oil escapes, and then the device remains closed. If the tank 21 is not full when the vessel sinks, then as the vessel sinks, the increasing hydrostatic pressure of the sea water forces the valve member 32 to open slightly and admit water until the inside and outside pressures are balanced. if the tank 21 is full, there is no access for water to force out the oil and the spring 37 holds the valve 32 closed with sufficient force so that there is unlikely to be any such pressure developing. The developing of additional pressure in the cylinder 45 has no ef fect, since the rod 44 bottoms on a portion 57 of the housing and cannot go any further, and even if it could, there would be no substantial effect. Thus, the tank 21 is locked closed and the contents are prevented from polluting the ocean.

in order that the portion of the valve 32 be observable from outside and to any observer, the pivot member 37 has an exterior indicator arm 58 secured thereto, which turns 90 with the pivot member 37 when the valve 32 closes. Electronic circuitry can also be connected to transmit a signal of the position of the valve to a remote indicator panel, which may be located in the vessels wheelhouse or in its engine room.

it may be possible, and if it is possible, it will, of course, be desirable, to salvage a substantial amount of oil from such a tank. To do this, a salvage ship 60, as shown in FIG. 12, locates the position of the sunken ship 20 and sends down a line 61 with a diver. The diver, on descending, comes to the closure fitting of one of the two vents 22 and 23. Upon determining the angle or trim of the vessel, he can select whichever vent 22 or 23 is higher than the other, and he should operate on the high vent 22. The closure fixture 25 is provided with a fitting such as a nipple 62 at one side that is normally closed completely snugly by a hose cap or threaded plug 63. The device 25 is also provided with a quadrant member 64 which indicates the position of a cam latch 65, which extends through the conduit 22 parallel to the valve seat 31 and may be used to hold the closure valve 32 completely closed at this time it is in an unlatched position, but the diver moves the quadrant 64 through a desired angle to 'move the cam latch 65 to a position where it engages a latch 66 on the valve member 32. Thus, there can thereafter be no drawing in of sea water at this particular vent even though the pressure inside the tank drops. The diver then uses a wrench that he has to withdraw the hose cap 63 and to attach a conduit 67 to it. This can be done with loss of very little oil done quickly and properly. With this attached, the salvage ship 60 begins pumping, and as it pumps, water flows into the tank 21 from the lower vent 23 by virtue of the decrease of pressure inside, and gradually fills up the tank 21, replacing the oil as it is withdrawn, keeping the pressures balanced.

As shown in FIG. 1, the tank 21 may have a typical ullage opening 70, with ullage cover 71 and a pair of Butterworth openings 72 closed by suitable covers 73. Also, the vent 22 may have at its mouth 24 (FIG. 8) a suitable ball valve stop 74, if desired, a vacuum relief valve 75, and a flame screen 76. FIG. 2 shows that filling may be via a deck fill header 77, a vertical line 78 and a bottom fill and discharge header 79, with the usual branches port and starboard to wing tanks. Also (see FIG. 1). a valve control 80 may be provided for a branch gate valve 81 having a suction and fill bell mouth 82 at each tank 21.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spiritand scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

We claim: 1. A shipboard storage tank for liquids, comprising in combination a vent and overflow conduit having an outlet, and an anti-pollution valve installed in said conduit and comprising closure means for automatically closing said conduit against the passage of liquids to said outlet, latching means for normally latching said closure means in the open position so as normally not to interfere with venting and overflow functions, pressure-actuated means for unlatching said latching means upon the application thereto of a predetermined pressure well above atmospheric pressure, a control conduit leading from the atmosphere to said pressure-actuated means and having orifice means therein preventing actuation of said pressure actuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when the ship sinks, and biasing means for normally holding the closure means closed after said unlatching, said biasing means including means for momentarily opening said closure means for inflow of ambient water through the outlet and into the interior of the storage tank when the ambient pressure outside the storage tank exceeds the internal pressure within the storage tank by an amount greater than the force exerted on the closure means by the biasing means.

2. The tank of claim 1 wherein said closure means includes a pivoted closure member and said biasing means include spring means for swinging said closure member to its closed position when said latching means is unlatched.

3. The tank of claim 1 wherein said closure means includes indicator means extending outside said conduit and outside said tank for giving visual indication of the position of said closure means.

4. The tank of claim 1 wherein said conduit means includes training means to prevent entry of foreign matter.

5. A shipboard storgage tank for liquids, comprising in combination a vent and overflow conduit having an outlet, and

an anti-pollution valve installed in said conduit and comprising closure means for automatically closing said conduit against the passage of liquids to said outlet,

latching means for normally latching said closure means in the open position so as normally not to interfere with venting and overflow functions,

pressure-actuated means for unlatching said latching means upon the application thereto of a predetermined pressure well above atmospheric pressure,

a control conduit leading from the atmosphere to said pressure-actuated means and having orifice means therein preventing actuation of said pressure actuated means by transient effects while e-nabling prompt actuation by the permanent hydrostatic pressure exerted by water when the ship sinks, and wherein said anti-pollution valve includes manually operable means exterior to said tank for locking said closure means in its closed position,

access means for affording access from outside said tank and said conduit to the interior of said vent and overflow conduit between said tank and said valve, and

means for attaching a pumping conduit from outside said tank to said access means, thereby enabling salvage of the contents of a said tank from a sunken vessel.

6. A shipboard storage tank for liquids, having an upper wall, comprising in combination a plurality of vent and overflow conduits, each having an outlet extending up from spaced-apart portions of said upper wall to provide conduit outlets at different levels when said tank and upper wall are inclined from the horizontal, and

an anti-pollution valve installed in each said conduit and comprising closure means for automatically closing said conduit against the passage of liquids to said outlet,

latching means for normally latching said closure means in the open position so as normally not to interfere with venting and overflow functions,

pressure-actuated means for unlatching said latching means upon the application thereto of a predetermined pressure well above atmospheric pressure, and

a control conduit leading from the atmosphere to said pressure actuated means and having an orifice therein preventing actuation of said pressurcactuated means by transie'nteffects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when the ship sinks, and

biasing means associated with each closure means for normally holding the closure means closed after said unlatching, said biasing means including means for momentarily opening said closure means for inflow of ambient water through the outlet and into the interior of the storage tank when the ambient pressure outside the storage tank exceeds the internal pressure within the storage tank by an amount greater than the force exerted on the closure means by the biasing means.

7. The tank of claim 6 wherein said closure means includes a pivoted closure member and said biasing means include spring means for swinging said closure member to its closed position when said latching means in unlatched.

8. The tank of claim 7 wherein each said antipollution valve includes manually operable means exterior to said tank for locking said closure member in its closed position, and

normally closed access means enabling attachment from outside said tank and from outside said vent and overflow conduits of a pumping conduit to the tank interior at a location closelyadjacent said closure member and on the tank side thereof,

thereby enabling salvage of the contents of said tank from the vent and overflow conduit to which the pumping conduit is attached while the antipollution valve of the other vent and overflow conduit permits inflow of ambient water to pressure balance the outflow of salvaged contents through said access means and pumping conduit.

9. An anti-pollution valve for installation in a vent and overflow conduit of a shipboard storage tank for liquids, comprising closure means for automatically closing said conduit against the passage of liquids to the outlet of said conduit,

latching means for normally latching said closure means in the open position so as normally not to interfere with venting and overflow functions,

pressure-actuated means for unlatching said latching means upon the application thereto of a predetermined pressure well above atmospheric pressure,

a control conduit leading from the atmosphere to said pressure actuated means and having an orifice therein preventing actuation of said pressureactuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when the ship sinks, and

biasing means for normally holding the closure means closed after said unlatching said biasing means including means for momentarily opening said closure means for inflow of ambient water through the outlet and into interior of the storage tank when the ambient pressure outside the storage tank exceeds the internal pressure within the storage tank by an amount greater than the force exerted on the closure means by the biasing means.

10. The tank of claim 9 wherein said closure means includes a pivoted closure member and-said biasing means include spring means for swinging said closure member to its closed position when said latching means is unlatched.

11. The anti-pollution valve of claim 9 wherein said closure means includes indicator means extending outside said conduit and giving visual indication ofthe position of said closure means.

12. The anti-pollution valve of claim 9 wherein said conduit means includes straining means to prevent entry of foreign matter.

13. An anti-pollution valve for installation in a vent and overflow conduit of a shipboard storage tank for liquids, comprising closure means for automatically closing said conduit against the passage of liquids to said outlet,

latching means for normally latching said closure means in the open position so as normally not to interfere with venting and overflow functions,

pressure-actuated means for unlatching said latching means upon the application thereto of a predetermined pressure well above atmospheric pressure, and a control conduit leading from the atmosphere to said pressure-actuated means and having an orifice therein preventing actuation of said pressureactuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when the ship sinks and wherein said anti-pollution valve includes manually operable means exterior to said tank for locking said closure means in its closed position,

access means for affording access from outside said tank and said conduit to the interior of said vent and overflow conduit between said tank and said valve, and

means for attaching a pumping conduit from outside said tank to said access means, thereby enabling salvage of the contents ofa said tank from a sunken vessel.

14. In a shipboard storage tank for liquids, the combination ofa vent and overflow conduit having an outlet, and

an anti-pollution valve installed in said conduit and comprising a valve housing having a valve seat, a closure member below said valve seat pivoted to said valve seat and having a latching dog thereon,

spring means urging said closure member to swing to its closed position against said seat, for automatically closing said conduit against the passage of liquids from said tank to said outlet,

latching means for normally engaging said dog and latching said closure member in the open position so as normally not to interfere with venting or overflow functions,

pressure-actuated means for moving said latching means away from said dog upon the application to said pressure actuated means of a predetermined pressure well above atmospheric pressure, and

a control conduit leading from the atmosphere to said pressure-actuated means and having a reduced-area passage preventing actuation of said pressure-actuated means by transient effects while spect to the valve seat as to permit momentary opening of the closure means and inflow of ambient water through the outlet and into the interior of the storage tank when the ambient presssure outside the storage tank exceeds the internal pressure within the storage tank by an amount greater than the force exerted on the closure means by the spring means.

15. In a shipboard storage tank for liquids, the combi- 10 nation of a vent and overflow conduit having an outlet,

enabling prompt actuation by the permanent hydrostatic pressure exerted by water when a vessel carrying the tank sinks, and wherein the closure means and spring means are so oriented with reand an anti-pollution valve installed in said conduit and comprising a valve housing having a valve seat.

a closure member below said valve seat pivoted to said valve seat and having a latching dog thereon.

spring means urging said closure member to swing to its closed position against said seat, for automatically closing said conduit against the passage of liquids from said tank to said outlet,

latching means for normally engaging said dog and latching said closure member in the open position so as normally not to interfere with venting or overflow functions,

pressure-actuated means for moving said latching means away from said dog upon the application to said pressure-actuated means of a predetermined pressure well above atmospheric pressure, and

a control conduit leading from the atmosphere to said pressure-actuated means and having a reducedarea passage preventing actuation of said pressure-actuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when a vessel carrying the tank sinks and wherein said valve housing comprises a nipple below said seat, and

a removable threaded plug normally closing said nip- V ple, whereby in a sunken ship the plug can be removed and a salvage line attached to said nipple. 16. In a shipboard storage tank for liquids, the combination of a vent and overflow conduit having an outlet, and

an anti-pollution valve installed in said conduit and comprising a valve housing having a valve seat,

a closure member below said valve seat pivoted to said valveseat and having a latching dog thereon,

spring means urging said closure member to swing to its closed position against said seat, for automatically closing said conduit against the passage of liq uids from said tank to said outlet,

latching means for normally engaging said dog and latching said closure member in the open position so as normally not to interfere with venting or overflow functions,

pressure-actuated means for moving said latching means away from said dog upon the application to said pressure-actuated means of a predetermined pressure well above atmospheric pressure, and

a control conduit leading from the atmosphere to said pressure-actuated means and having a reduced-area passage preventing actuation of said pressure-actuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when a vessel carrying the tank sinks and wherein said valve housing comprises a nipple below said seat, and

a removable threaded plug normally closing said nipwhereby in a sunken ship the plug can be removed and a salvage line attached to said nipple, and

a first locking member on said closure member on the side which closes against said seat, and

a second locking member having a handle extending outside said valve housing and indicating the position thereof,

whereby an operator can move said handle to cause said second locking member to engage said first locking member and thereby hold said closure member locked in its closed position against said seat.

17. A shipboard storage tank for liquids, comprising in combination:

a conduit leading from an upper end of said tank and having an outlet open to the atmosphere, and

an anti-pollution valve installed in said conduit and comprising closure means for automatically closing said conduit against the passage of liquids to said outlet, latching means for normally latching said closure means in the open position so as normally not to interfere with venting and overflow functions, and means for unlatching said latching means upon said outlet reaching a predetermined depth when the ship sinks, and

biasing means for normally holding the closure means closed after said unlatching, said biasing means including means for momentarily opening said closure means for inflow of ambient water through the outlet and into the interior of the storage tank when the ambient pressure outside the storage tank exceeds the-internal pressure within the storage tank by an amount greater than the force exerted on the closure means by the biasing means.

18. A valve unit for a ship borne storage tank of the kind used to transport liquids such as petroleum products and chemicals and normally vented to ambient atmosphere through a vent opening of at least one vent conduit, said valve unit comprising,

an outer housing for connection to the vent conduit to control all fluid flow both out of the conduit from the tank and into the conduit to the tank,

a valve seat defining an opening for fluid flow into and out of the vent conduit and storage tank,

a valve element movable with respect to the valve seat between open positions off the valve seat and a closed position against the valve seat,

biasing means for biasing the valve element to the closed position,

retaining means operatively associated with the valve element for retaining the valve element in a first open position for free flow of vent gases through the vent opening and into and out of the storage tank, and

ambient pressure responsive means operatively connected to the retaining means and actuated in response to a certain level of ambient pressure corresponding to submergence of the valve unit to a certain underwater depth for disassociating the retaining means from the valve element to permit the biasing means to move the valve element to the closed position,

said biasing means, following actuation of the ambient pressure responsive means, normally holding the valve element in the closed position to prevent outflow of fluid from the storage tank through the vent opening, said biasing means including means for momentarily opening said valve by movement of the valve element off the valve seat and against the biasing means when the ambient pressure outside the valve housing exceeds the pressure on the tank side of the valve seat by more than the force of the biasing means,

whereby the valve unit prevents polluting outflow of liquid from the sunken storage tank while while said means for momentarily opening said valve enables sufficient inflow of ambient water into the storage tank to maintain the differential between the ambient pressure outside the tank and the internal pressure within the tank at a level that will not rupture the tank.

19. The valve unit of claim 18 including a nipple on the housing on the tank side of the valve seat and cap means removably connected to the nipple whereby the cap means can be removed and a salvage hose connected to the nipple to pump liquid out of the tank while the valve element remains engaged with the valve seat in the closed position.

20. The tank of claim 1 wherein said closure means include:

a. a valve seat facing the interior of the tank and de fining an opening for fluid flow into and out of the vent and overflow conduit,

b. a movable valve element in said tank engageable with the inwardly facing valve seat in a closed position,

said biasing means cooperating with said valve element to exert a biasing force on said valve element in a direction to move said valve element into engagement with said inwardly facing valve seat and to hold it there, facing outwardly from said tank, and

c. mounting means mounting said valve element for opening movement away from said valve seat in a direction toward the interior of the tank and against the force exerted by said biasing means,

whereby high ambient pressures on the outside of the tank and exerted against said valve element can move the valve element inwardly of the tank off the valve seat until the pressure differential between the pressure outside and the pressure inside of the tank is lowered to the level of the force exerted by said biasing means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENTNO.: 3,868,921 DATED March 4, 1975 INVENTOR(S) David Jackson Seymour, Norman MacRitchie,

. rker J. atthews Th as A. l r It rs certlfred tir at error appears rn the above-identiffia patent andThat saIIi Letters Patent are hereby corrected as shown below:

Item [73] Assignees: "William E. Boeing" should read --William E. Boeing, Jr. Abstract, line 17, "dump" should read --pump--.

Column 1, line 28, "required" should read -requires--. Column 3, line 29, "is view" should read --is a view--. Column 3, line 56, "each tanks" should read -each tank-. Column 4, line 32, "vention" should read --venting--. Column 4, lines 49-50, "incoporates" should read --incorporates-. Column 5, line 28, "coming through" should read --coming in through--. Column 5, line 52, "portion" should read position--. Column 6, line 18, 'oil done" should read --oil if done--. Column 7, line 17, which is line 2 of claim 4, "training means" --straining means--.

Signed and Scaled this twenty-first Day of October 1975 [SEAL] Attest:

RUTH c. MASON c. MARSHALL DANN Arresting Officer Commissioner u/Patenrs and Trademarks 

1. A shipboard storage tank for liquids, comprising in combination a vent and overflow conduit having an outlet, and an anti-pollution valve installed in said conduit and comprising closure means for automatically closing said conduit against the passage of liquids to said outlet, latching means for normally latching said closure means in the open position so as normally not to interfere with venting and overflow functions, pressure-actuated means for unlatching said latching means upon the application thereto of a predetermined pressure well above atmospheric pressure, a control conduit leading from the atmosphere to said pressureactuated means and having orifice means therein preventing actuation of said pressure actuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when the ship sinks, and biasing means for normally holding the closure means closed after said unlatching, said biasing means including means for momentarily opening said closure means for inflow of ambient water through the outlet and into the interior of the storage tank when the ambient pressure outside the storage tank exceeds the internal pressure within the storage tank by an amount greater than the force exerted on the closure means by the biasing means.
 2. The tank of claim 1 wherein said closure means includes a pivoted closure member and said biasing means include spring means for swinging said closure member to its closed position when said latching means is unlatched.
 3. The tank of claim 1 wherein said closure means includes indicator means extending outside said conduit and outside said tank for giving visual indication of the position of said closure means.
 4. The tank of claim 1 wherein said conduit means includes training means to prevent entry of foreign matter.
 5. A shipboard storgage tank for liquids, comprising in combination a vent and overflow conduit having an outlet, and an anti-pollution valve installed in said conduit and comprising closure means for automatically closing said conduit against the passage of liquids to said outlet, latching means for normally latching said closure means in the open position so as normally not to interfere with venting and overflow functions, pressure-actuated means for unlatching said latching means upon the application thereto of a predetermined pressure well above atmospheric pressure, a control conduit leading from the atmosphere to said pressure-actuated means and having orifice means therein preventing actuation of said pressure actuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when the ship sinks, and wherein said anti-pollution valve includes manually operable means exterior to said tank for locking said closure means in its closed position, access means for affording access from outside said tank and said conduit to the interior of said vent and overflow conduit betweeN said tank and said valve, and means for attaching a pumping conduit from outside said tank to said access means, thereby enabling salvage of the contents of a said tank from a sunken vessel.
 6. A shipboard storage tank for liquids, having an upper wall, comprising in combination a plurality of vent and overflow conduits, each having an outlet extending up from spaced-apart portions of said upper wall to provide conduit outlets at different levels when said tank and upper wall are inclined from the horizontal, and an anti-pollution valve installed in each said conduit and comprising closure means for automatically closing said conduit against the passage of liquids to said outlet, latching means for normally latching said closure means in the open position so as normally not to interfere with venting and overflow functions, pressure-actuated means for unlatching said latching means upon the application thereto of a predetermined pressure well above atmospheric pressure, and a control conduit leading from the atmosphere to said pressure actuated means and having an orifice therein preventing actuation of said pressure-actuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when the ship sinks, and biasing means associated with each closure means for normally holding the closure means closed after said unlatching, said biasing means including means for momentarily opening said closure means for inflow of ambient water through the outlet and into the interior of the storage tank when the ambient pressure outside the storage tank exceeds the internal pressure within the storage tank by an amount greater than the force exerted on the closure means by the biasing means.
 7. The tank of claim 6 wherein said closure means includes a pivoted closure member and said biasing means include spring means for swinging said closure member to its closed position when said latching means in unlatched.
 8. The tank of claim 7 wherein each said anti-pollution valve includes manually operable means exterior to said tank for locking said closure member in its closed position, and normally closed access means enabling attachment from outside said tank and from outside said vent and overflow conduits of a pumping conduit to the tank interior at a location closely adjacent said closure member and on the tank side thereof, thereby enabling salvage of the contents of said tank from the vent and overflow conduit to which the pumping conduit is attached while the anti-pollution valve of the other vent and overflow conduit permits inflow of ambient water to pressure balance the outflow of salvaged contents through said access means and pumping conduit.
 9. An anti-pollution valve for installation in a vent and overflow conduit of a shipboard storage tank for liquids, comprising closure means for automatically closing said conduit against the passage of liquids to the outlet of said conduit, latching means for normally latching said closure means in the open position so as normally not to interfere with venting and overflow functions, pressure-actuated means for unlatching said latching means upon the application thereto of a predetermined pressure well above atmospheric pressure, a control conduit leading from the atmosphere to said pressure actuated means and having an orifice therein preventing actuation of said pressure-actuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when the ship sinks, and biasing means for normally holding the closure means closed after said unlatching said biasing means including means for momentarily opening said closure means for inflow of ambient water through the outlet and into interior of the storage tank when the ambient pressure outside the storage tank exceeds the internal pressure within the storage tank by an amount greater than the foRce exerted on the closure means by the biasing means.
 10. The tank of claim 9 wherein said closure means includes a pivoted closure member and said biasing means include spring means for swinging said closure member to its closed position when said latching means is unlatched.
 11. The anti-pollution valve of claim 9 wherein said closure means includes indicator means extending outside said conduit and giving visual indication of the position of said closure means.
 12. The anti-pollution valve of claim 9 wherein said conduit means includes straining means to prevent entry of foreign matter.
 13. An anti-pollution valve for installation in a vent and overflow conduit of a shipboard storage tank for liquids, comprising closure means for automatically closing said conduit against the passage of liquids to said outlet, latching means for normally latching said closure means in the open position so as normally not to interfere with venting and overflow functions, pressure-actuated means for unlatching said latching means upon the application thereto of a predetermined pressure well above atmospheric pressure, and a control conduit leading from the atmosphere to said pressure-actuated means and having an orifice therein preventing actuation of said pressure-actuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when the ship sinks and wherein said anti-pollution valve includes manually operable means exterior to said tank for locking said closure means in its closed position, access means for affording access from outside said tank and said conduit to the interior of said vent and overflow conduit between said tank and said valve, and means for attaching a pumping conduit from outside said tank to said access means, thereby enabling salvage of the contents of a said tank from a sunken vessel.
 14. In a shipboard storage tank for liquids, the combination of a vent and overflow conduit having an outlet, and an anti-pollution valve installed in said conduit and comprising a valve housing having a valve seat, a closure member below said valve seat pivoted to said valve seat and having a latching dog thereon, spring means urging said closure member to swing to its closed position against said seat, for automatically closing said conduit against the passage of liquids from said tank to said outlet, latching means for normally engaging said dog and latching said closure member in the open position so as normally not to interfere with venting or overflow functions, pressure-actuated means for moving said latching means away from said dog upon the application to said pressure actuated means of a predetermined pressure well above atmospheric pressure, and a control conduit leading from the atmosphere to said pressure-actuated means and having a reduced-area passage preventing actuation of said pressure-actuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when a vessel carrying the tank sinks, and wherein the closure means and spring means are so oriented with respect to the valve seat as to permit momentary opening of the closure means and inflow of ambient water through the outlet and into the interior of the storage tank when the ambient presssure outside the storage tank exceeds the internal pressure within the storage tank by an amount greater than the force exerted on the closure means by the spring means.
 15. In a shipboard storage tank for liquids, the combination of a vent and overflow conduit having an outlet, and an anti-pollution valve installed in said conduit and comprising a valve housing having a valve seat, a closure member below said valve seat pivoted to said valve seat and having a latching dog thereon, spring means urging said closure member to swing to its closed position against said seat, for automatically closing Said conduit against the passage of liquids from said tank to said outlet, latching means for normally engaging said dog and latching said closure member in the open position so as normally not to interfere with venting or overflow functions, pressure-actuated means for moving said latching means away from said dog upon the application to said pressure-actuated means of a predetermined pressure well above atmospheric pressure, and a control conduit leading from the atmosphere to said pressure-actuated means and having a reduced-area passage preventing actuation of said pressure-actuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when a vessel carrying the tank sinks and wherein said valve housing comprises a nipple below said seat, and a removable threaded plug normally closing said nipple, whereby in a sunken ship the plug can be removed and a salvage line attached to said nipple.
 16. In a shipboard storage tank for liquids, the combination of a vent and overflow conduit having an outlet, and an anti-pollution valve installed in said conduit and comprising a valve housing having a valve seat, a closure member below said valve seat pivoted to said valve seat and having a latching dog thereon, spring means urging said closure member to swing to its closed position against said seat, for automatically closing said conduit against the passage of liquids from said tank to said outlet, latching means for normally engaging said dog and latching said closure member in the open position so as normally not to interfere with venting or overflow functions, pressure-actuated means for moving said latching means away from said dog upon the application to said pressure-actuated means of a predetermined pressure well above atmospheric pressure, and a control conduit leading from the atmosphere to said pressure-actuated means and having a reduced-area passage preventing actuation of said pressure-actuated means by transient effects while enabling prompt actuation by the permanent hydrostatic pressure exerted by water when a vessel carrying the tank sinks and wherein said valve housing comprises a nipple below said seat, and a removable threaded plug normally closing said nipple, whereby in a sunken ship the plug can be removed and a salvage line attached to said nipple, and a first locking member on said closure member on the side which closes against said seat, and a second locking member having a handle extending outside said valve housing and indicating the position thereof, whereby an operator can move said handle to cause said second locking member to engage said first locking member and thereby hold said closure member locked in its closed position against said seat.
 17. A shipboard storage tank for liquids, comprising in combination: a conduit leading from an upper end of said tank and having an outlet open to the atmosphere, and an anti-pollution valve installed in said conduit and comprising closure means for automatically closing said conduit against the passage of liquids to said outlet, latching means for normally latching said closure means in the open position so as normally not to interfere with venting and overflow functions, and means for unlatching said latching means upon said outlet reaching a predetermined depth when the ship sinks, and biasing means for normally holding the closure means closed after said unlatching, said biasing means including means for momentarily opening said closure means for inflow of ambient water through the outlet and into the interior of the storage tank when the ambient pressure outside the storage tank exceeds the internal pressure within the storage tank by an amount greater than the force exerted on the closure means by the biasing means.
 18. A valve unit for a ship borne storage tank of the kind used to transport liquids such as Petroleum products and chemicals and normally vented to ambient atmosphere through a vent opening of at least one vent conduit, said valve unit comprising, an outer housing for connection to the vent conduit to control all fluid flow both out of the conduit from the tank and into the conduit to the tank, a valve seat defining an opening for fluid flow into and out of the vent conduit and storage tank, a valve element movable with respect to the valve seat between open positions off the valve seat and a closed position against the valve seat, biasing means for biasing the valve element to the closed position, retaining means operatively associated with the valve element for retaining the valve element in a first open position for free flow of vent gases through the vent opening and into and out of the storage tank, and ambient pressure responsive means operatively connected to the retaining means and actuated in response to a certain level of ambient pressure corresponding to submergence of the valve unit to a certain underwater depth for disassociating the retaining means from the valve element to permit the biasing means to move the valve element to the closed position, said biasing means, following actuation of the ambient pressure responsive means, normally holding the valve element in the closed position to prevent outflow of fluid from the storage tank through the vent opening, said biasing means including means for momentarily opening said valve by movement of the valve element off the valve seat and against the biasing means when the ambient pressure outside the valve housing exceeds the pressure on the tank side of the valve seat by more than the force of the biasing means, whereby the valve unit prevents polluting outflow of liquid from the sunken storage tank while while said means for momentarily opening said valve enables sufficient inflow of ambient water into the storage tank to maintain the differential between the ambient pressure outside the tank and the internal pressure within the tank at a level that will not rupture the tank.
 19. The valve unit of claim 18 including a nipple on the housing on the tank side of the valve seat and cap means removably connected to the nipple whereby the cap means can be removed and a salvage hose connected to the nipple to pump liquid out of the tank while the valve element remains engaged with the valve seat in the closed position.
 20. The tank of claim 1 wherein said closure means include: a. a valve seat facing the interior of the tank and defining an opening for fluid flow into and out of the vent and overflow conduit, b. a movable valve element in said tank engageable with the inwardly facing valve seat in a closed position, said biasing means cooperating with said valve element to exert a biasing force on said valve element in a direction to move said valve element into engagement with said inwardly facing valve seat and to hold it there, facing outwardly from said tank, and c. mounting means mounting said valve element for opening movement away from said valve seat in a direction toward the interior of the tank and against the force exerted by said biasing means, whereby high ambient pressures on the outside of the tank and exerted against said valve element can move the valve element inwardly of the tank off the valve seat until the pressure differential between the pressure outside and the pressure inside of the tank is lowered to the level of the force exerted by said biasing means. 